![]() The I/O devices in this case have been assigned distinct read and write control lines. Therefore, separate instructions for reading and writing are present for both I/O and memory. These distinct spaces specially allotted for the I/O peripherals are called as ‘Ports’. I/O Mapped I/O devices are also called isolated I/O mapping as the I/O devices are allotted separate addressing space from the memory. The assemble language instructions namely LOAD and STORE are utilized to execute the read and write operations from both the I/O peripherals and the memory. In a memory-mapped I/O peripheral, the data from the I/O device is sent to the ALU (arithmetic and logical unit). A control signal is activated whenever an address is sent over the address line. The same set of instructions is used for the transfer of data to and from the I/O or the memory. In this scenario, the I/O ports are considered memory locations used for performing the writing and reading operations. The memory-mapped I/O interfacing is used in applications having small memory requirements. As a result, this minimizes the addressing and memory capacity. Moreover, I/O devices and memory share the same bus to transfer data to and from the processor. A 16-bit address is assigned for the I/O devices in the memory. In the case of memory-mapped I/O peripherals no separate memory is allocated for I/O devices, i.e., they share the same memory. Memory-Mapped I/O devices are treated as memory locations and not any separate I/O peripherals. But before that let’s look into their basic introductions. In this article, we will be highlighting the significant differences between Memory-Mapped I/O Interfacing and Standard I/O Mapped I/O Interfacing. Based on the kind of interfacing link between CPU and I/O devices, it can be subdivided into the following two categories – I/O interfacing is defined as the interfacing existing between the processing unit or CPU and I/0 devices such as – keyboard, mouse, printer, etc. An interface is the communication link between the CPU and the external peripheral devices. The microprocessor is connected with external devices such as the I/O devices, memory, and other peripherals via a link called the Interface. This article describes the difference between Memory-mapped I/O and I/O-mapped I/O.
0 Comments
Leave a Reply. |